Power gas generating cartridge



E. WHITWORTH EI'AL POWER GAS GENERATING CARTRIDGE Filed NMIB-'26, 1946 MH s lo 1n www. m W; 1l 9 DM/ m .mM/ wo. /A es w Nov. 14, 1950 v FIG. 1.

Patented Nov. 14, 1950 UNITED STATES vEntrer;'r oFVF Edward Whitworth, West Kilbride, and Thomas v Thomson; Kilmarnock, Scotland, assignors to Imperial Chemical Industries Limited, a corporation of Great Britain Y Applicationy November 26, 1946, Serial No.- 712,268 In .GreatBritain NovermberrZG, 17945 The present invention relates to a new or modied construction of power gas generating blank cartridges such as are suitable Yfor the generation of gases ,under pressure in the actuation of mechanical devices, for instanceV internal combustion engine starter cartridges. In particular the invention relates to an improved or modied method of assembling power gas generating blank cartridges 4provided with certain successive kindling elements, to which reference will be made hereinunder, whereby the risk of failurerof anelectric fuzehead or a percussion capj to bring about the proper ignition oi said kindling elementsfis minimised.

The combustible gas producing charges in power gask generating blank cartridges usually consist mainly of smokeless powder forms of comparativelylarge grain sizes that cannot be directly ignitedby the lelectric fuzehead or percussion cap employed as ignition means for the cartridges. More generally, it may be stated that it is impracticable to employ for any substantial portion of the combustible charge a combustible material of such form or composition as to be easily ignited directly from the electric fuzehead or percussion cap, since otherwise the rate of combustion of such material would become explosive as the pressure increased, so that the rate of pressure generation would become suicient todamage the mechanism it is required to operate.y A small quantity of compositiondirectly ignitable by the lelectric fuzehead or percussion cap is therefore used as an intermediate kindling charge, and it is frequently, necessary to employ a gas producing charge comprising more than one portion of dif- Tering forms or compositionsin successive ignition relationship with said intermediate kindling charge and. with one another. For instance the combustiblegas producing charge for anrengine starter cartridge whereof the contents are intended to beV ejected in iiaming condition from the cartridge case frequently comprises smokeless powder pellets of two differing sizes or compositions, one of which is lessV easily extinguished s claims. (o1. 1oz-39) of the partition. I-Iitherto it has been the practice to supportuthe disc or cup bearing the coat; ing directly ignitabl'e bythe fuzehead,"for7in stance a, Celluloid disc or cup coated with black powder, on the side next to the fuzehead upon the haphazardly disposed grains of smokeless powder or the like surrounding the iuzehead, which is protected by an open ended sheath. l

It is reasier to insert this disc properly 'in position within the cartridge case if its diameter is substantially eq-ual to the internal diameter of the said case. If during the insertion the discv is slightly crumpled ready es'caperofkgas from beneath it is permitted when the disc is ignited but itis uncertain that this crumpling wi11 always occur. Furthermore, if, for example, the black powder coated disc issupported clear of the fuzehead by meansof a tubular spacing member of combustible materialv resting on the base oiv the cartridge gasescapes past it still less readily and it is sometimes found that the gas pressure beneath thedisc just after thefuzehead is ignited may be such that on`occasion the disc is` blown forward a little and instead of getting properly ignitedit merely zzles and goes out` again, thus giving rise to a misre.

The object of the present invention is to proi vide a well fitting disc or cupof the aforesaid on ejection, or more easily ignited, than the other, as well as an intermediate kindling composition directly ignitable by the electric Luzehead or percussion cap.

In practice, electrically ignitable power gas generating Lblank cartridges frequently include for kindling purposes in the proximity ofa fuzew head at the base of the cartridge a disc or cup of combustible material extending across the cartridge case and having a deagrating powdercoating capable of direct ignition from the fuzehead, a portion of a combustible charge in the form of grains capable of being ignited from' bustible charge being situated on the distal side kind in electrically or percussion ignitable power gas generating blank cartridges which will permit the ready escape of gas from beneath it.

According to the present invention power gas generating blank cartridges of the kind wherein thereis provided in the proximity of an exposed portion of the electrical orV percussionV ignition means at the cartridge base a partition of combustible material extending across the cartridge andbearing on` its proximal side a deiiagrating powder. coating capable of direct ignition from said electrical. or percussion ignition means and of igniting aportion ofthe combustible charge disposed on said proximal side of the partition are characterised in that the said partition is provided with at least one perforator.

The said partitionk of combustible materialy Vis preferably of Celluloid 'coated ont its4 proximal sidev with black powder .and where more than one `perforation is provided the said'lperforations are preferably regularly disposed and Well spaced one from the other. p Ii desired, especially in the case where ignition means are electrical, the perforated ,partif tion is supported clear of the electricalignition means i. e.- the fuzehead by Ymeans of a tubular spacing member of combustible material rest'- ing on said base. i

The said tubular spacing member may advantageously be made ofv smokeless powder or of Celluloid'and may take the form of a cylindrical annulus orfv outer diameter slightly less than the internal diameter of the cartridge case. It will be member is thin enough to allow of the haphazard Y disposition of grains of smokeless powder or the like around the fuzehead, which is desirably protected by means of an open-ended tubular sheath,

in the space between the base of the cartridge and the coated side of the partition so that the d e` Ilagrating powder coating can be ignited'by Vthe Y fuzehead and in turn ignite the powder grains. The length of the tubular spacing member is sufficient to ensure that even under loading pressure conditions the powder coated partition will nowhere touch the exposed portion of the fuzehead, nor compress anyjsolid particles against it. V In loading the cartridge, -the tubular spacing member may be 'inserted into `the base of the cartridge case already containing the electric fuzehead provided with its open-ended protecting sheath, a portion of the combustible charge in the form of grains may then be poured or run intothe cartridgein quantity insufficient to extend as far as the end of the Ytubular spacing member. The powder coated perforated partition may then be seated on the end'of the tubular spacing member with the powder coated surface facing the exposed end'of the fuzehead.

The remainder of the combustible charge may then be loaded on the distal side of the partition yand the end of the cartridge case turned over a terminal disc of Celluloid or other combustible material in known manner.

VTwo forms of electrically ignitable power gas generating blank cartridges according to the invention are illustrated in the diagrammatic drawing accompanying the specification in which Fig. 1 is a vertical axial cross section of a cartridge provided with a perforated Celluloid cup, supported by a Celluloid ring. Fig. 2 is a vertical axial cross section of a blank cartridge provided with a perforated Celluloid cup supported on haphazardly disposedl smokeless powder pellets, and

Fig. 3 isa plan view of the base of the Celluloid Referring to Fig. 1, I is a metal cartridge base having a central perforation 9. 2 and 4 are base wads of insulating material. 3 is a paper cartridge case wall.' I2 is an electric fuzehead of which onev of the terminal leading strips I0 is earthed to the metalcartridge base I while the other wholly insulated with wads 2 and 4 is eX.- posed as a live terminal at the aperture 9.y I4 is a tubular spacing member in the form of a Celluloid ring and I3 is a tubular protecting sheath for thefuzehead in the form of a piece of rubber tubing. 6 is a Celluloid cup provided with perforations 'I and bearing a coating of black powder 8 attached .to it.y 5, are haphazardly disposed smokeless powder pellets. The powder coating 8 is capable of direct ignition from the fuzehead I2 andthe pellets 5.are capable of direct ignition freni the powder coating 8. II is a further layer ofnsrnokeless powder pellets similar tothe pellets 5, I5 Visa longitudinal perforated cylindricalrod of smokeless powder composition and I6 is a Celluloid disc.

Fig. 2 is similar to Fig. 1 except that there is no Celluloid ring I4.

Fig. 3 is a plan View of the base of the perforated Celluloid cupA 6 shown in Figs. 1 and 2 showing the seven perforations 1 provided therein.

We claim:

1. An electrically ignitable power gas generating blank cartridge comprising a cylindrical paper casing, a metal base at one end of the casing, an electric fuzehead supported within the casing near the base, an open-ended, tubular sheath surrounding the fuzehead, a partition of combustible material extending across the cartridge bearing on its proximal side a deagrating powder-coating capable of direct ignition from said electric fuZehead, said combustible partition being provided with a plurality of perforations regularly spaced from one another across the area of the partition, a tubular spacing member for retaining the partition at a predetermined distance from the top of said fuzehead, smokeless powder pellets haphazardly distributed in the space between said partition and the cartridge base, and a second charge of smokeless powder positioned within the cartridge casing above saidperforated partition.

2. Appower gas generating. blank cartridge of the type whereinl there is provided, in the proximity of an exposed portion of an ignition means at the cartridge base, a partition of combustible material extending across the cartridge and bearing on its proximal side a deflagrating powder coating capable of direct ignition by said ignition means and of igniting a portion of the combustible charge disposed on said proximal side of the partition characterized in that said partition is provided with atleast one perforation. v

3. A lpower gas generating blank cartridge as set forth in claim 2 wherein the cartridge is electrically ignitable and the perforated partition is supportedclear of the electric ignition means by means of a tubular spacingfmember of combustible material resting on said base.

4. A power gas generating blankcartridge as set forth in claimj3 whereinthe Ytubular spacing member comprises smokeless powder.

v5. A power gas generating blank cartridge as set forth in claim 4 wherein the tubular spacing member is in the' form of a cylindrical annulus of outer diameter .slightly less than the internal diameter of the cartridge case.

6. A power gas generating blank cartridge as set: forth in claim 2 wherein the said partition of combustible material is of Celluloid coated on its proximal sidewith black powder. 7. A power gas generatingblank cartridge as set forth in claim 2 wherein a plurality of perforations is provided and the said yperforations are regularly disposed and well spaced one from the other.V I

f 8. A power gas generating blank cartridge as set forth in claim 2 wherein said ignition means is protected by means'of an open-ended tubular sheath in the space between the base o f the voartridge and the coated end of the partition in direct ignition relationshipwith the said ignition means.

' EDWARD WHITWORTH.

` THOMAS THOMSON.

- REFERENCES CITEi) The following references are of record in the me gf thiis'patennz" y Y UNITED STATES PATENTS Number 'Name Date 399,879 Graydon L' 1 Mar. 19, 1889 682,364 Mangon Sept.- 10, 1901 1,754,987 Driggsl et al. Apr. 15, 1930 2,207,936 Nardone 1 July16, 1940 2,362,927 Pratt I Nov.A 14, 1944 2,398,683 Whitworth et al. v Apr. 16, 1946 i. l i FOREIGN' PATENTS Number Y. Country VDate 129,668 Great Britain July 24, 1919 

